In numerous installations, a water pump and the electric motor which operates the water pump are submerged within the body of water from which water is pumped. In some water pump installations, a water pump and an electric driving motor may be located a considerable distance from the electric control unit which supplies electrical energy to the electric motor. In each water pump installation, there is a possibility that the supply of water at the pump may cease or a coupling between the driving electric motor and the water pump may break, or for some other reason the electric motor operates without pumping operation of the water pump. If the supply of water to the water pump ceases, the pump may be severely damaged if it is operated. If the coupling between the electric motor breaks or for some other reason the pump is operated without pumping action, a signal should be provided in regard to such a condition, and/or the motor should be deenergized.
Numerous types of water pump protector devices and indicator or signal circuits have been devised. Most of the pump protector devices require a separate mechanism to sense the water level condition and to provide a signal for manual or automatic deenergization of the electric driving motor. However, such devices require a separate electric circuit which extends from the body of water to the electric motor control unit. In most installations, the distances between the body of water and the electric motor control unit may be considerable and require long lengths of electric wire, as well as requiring a separate mechanism at the water level or in the body of water. Therefore, such protective devices have disadvantages. Pump protective or pump malfunction indicator devices and circuits which do not require separate mechanisms or circuits are usually complex and costly and are therefore objectionable.
The following patents disclose electric motor and/or liquid pump protective devices: 2,953,722, 3,417,290, 3,519,910, 3,600,657, 3,727,103, 3,931,559, 3,953,777, 4,034,269, 4,091,433, 4,117,408, 4,286,925, 4,290,007, 4,420,787, 4,642,478, 4,703,387.
In the past, each of the following units has been housed in a separate enclosure:
1. The voltage controlled motor start relay: This device is one of the more versatile devices for energization of capacitor-start induction-run motors. The relay is normally closed and the relay coil is connected in parallel with the start winding of the pump motor. As the counter electromotive force of the motor increases, the voltage applied to the relay coil increases and the relay operates. The start capacitor and the motor start winding are thus switched out of the circuit.
2. The motor start capacitor: This capacitor is connected in series with the start winding during starting operation. As the motor speed increases to near running speed the motor counter EMF increases and operates the motor start relay, switching out the capacitor and the motor start winding.
3. The motor running capacitor: In some cases a running capacitor is permanently connected in parallel with the running winding of the motor. The normal use of this capacitor is to increase the overall operating efficiency of the pump motor.
It is an object of this invention to provide electrical circuitry through which electrical energy is supplied to an electric motor which operates a liquid pump and in which the electrical circuitry deenergizes the electric motor if, for any reason, the liquid pump is not pumping liquid. Thus, it is an object of this invention to provide electrical circuitry which protects the liquid pump against damage and which may also serve as an indicator that the electric motor is operating without pumping action in the pump.
Another object of the invention is to provide a set of electric motor control components which is capable of operation of any one of a multiplicity of capacitor-start induction-run motors.
It is another object of the invention to provide means by which all of the motor control components are located within a single cabinet.
It is another object of this invention to provide in a single enclosure a complete versatile, substantially universal three wire pump motor start apparatus, which is uniquely configured and capable of starting and operating and controlling any capacitor start electric motor having a horsepower rating in the range of one-third horsepower to one and one-half horsepower. This combination provides for the installation of a single enclosure and for electrical connection to only a minimum number of electrical conductors therein. Thus, a plurality of separately mounted units is eliminated.
It is another object of this invention to provide such electrical circuitry and apparatus which is relatively low in cost to produce and install.
Other objects and advantages of this invention reside in the construction of parts, the combination thereof, the method of production, and the mode of operation, as will become more apparent from the following description.